During the common process of nutrition dietary proteins are presented to the immune system via the gastro-intestinal tract without an immune response to the ingested nutrients. This unresponsiveness is called oral immune tolerance or oral tolerance. The induction of oral immune tolerance is especially relevant for infants, who after birth are exposed for the first time to dietary proteins and have to adapt to this. If in infants oral immune tolerance is not established, food allergy will occur. Persons suffering from food allergy require a diet in which the specific food protein is avoided.
For infants suffering from allergy to cow's milk protein infant formulae are on the market comprising extensively hydrolysed proteins (extensive protein hydrolysate) or even merely free amino acids as nitrogen source. In these formulae no allergenic protein or peptides are present.
Infants born from parents of whom one or both suffers from an atopic disease, or who have one or more siblings suffering from an atopic disease, have a higher risk of becoming allergic to dietary proteins. For this group, besides the preferred breast feeding, hypoallergenic formulae are on the market, comprising a partial protein hydrolysate (partially hydrolysed proteins). These partially hydrolysed proteins have a decreased allergenicity. This approach has been demonstrated to be efficient in order to prevent sensitization by native proteins present in the adapted formulae. Typically, the extent of hydrolysis of proteins is less than those of extensively hydrolysed proteins for babies already suffering from allergy. These formulations have the advantage that they not only reduce the risk of developing an allergic response by preventing sensitization to the protein, but also induce orally an immunological tolerance to the intact protein. This has the advantage that later on the native protein can be introduced in the diet, with a reduced risk on allergic reactions.
EP 1 557 096 discloses infant food with low-allergenic casein hydrolysate and probiotic strains of lactic acid bacteria. For tolerance induction a partial whey protein hydrolysate is preferred.
EP 2 044 851 discloses a nutritional composition with partially hydrolysed milk protein having a degree of hydrolysis between 15% and 25% and 50 to 1000 ng of TGF-beta per 100 ml for the primary prevention of allergic reactions to dietary protein and the prevention of development of atopic diseases in young mammals.
EP 0 629 350 discloses the use of non-allergenic whey protein hydrolysates which are said to be capable of inducing cow's milk protein tolerance.
EP 0 827 697 discloses the use of whey, that has been hydrolysed enzymatically for the preparation of compositions that induce oral tolerance to cows' milk in susceptible mammals. The whey has a level of immunological detection of allergenic proteins >=100 times less than that of unhydrolysed whey.
WO 00/42863 discloses a hypoallergenic composition for the induction of protein tolerance in at risk infants of protein allergy, comprising a non allergenic protein extensively hydrolysed basis and/or a free amino acid basis, said composition comprising as the active ingredient at least one tolerogenic peptide of the allergenic protein.
However, the hypoallergenic compositions of the prior art often provide their effects just by avoiding the presence of potential allergens thereby providing only a secondary prevention effect and/or they require the presence of special ingredients such as probiotics or growth factors.
Still there is a need for nutrition for subjects at risk of developing or suffering from food allergy with improved effects on immune tolerance induction.
Thus, the technical problem underlying the present invention is to provide compositions, methods and means for overcoming the above-identified disadvantages, in particular an improved oral tolerance, in particular providing an improved primary allergy-preventing effect, against dietary proteins in humans, in particular humans at risk for developing a food allergy.